Fuse



Juiy 3Q, 194 w. F. ERRIG ET AL fi fi FUSE Filed April 20, 1942 IN VEN TORj.

ATTORNEY 600 miles per hour.

Patented July 30, 1946 FUSE William F. Errig and Edward S. De Hart, Philadelphia, Pa., assignors to Peco Manufacturing Corporation, Philadelphia, Pa., a corporation of Pennsylvania Application April 20, 1942, Serial No. 439,614

2 Claims. 1

Thi invention relates to fuses and more particularly to a nose fuse for bombs.

Dive bombing make it necessary to provide bomb fuses which can be armed at speeds up to It is also desirable to make bomb parts of less expensive, readily available materials, such as low grade steel. Bomb fuses heretofore employed are found unsatisfactory at the high speeds of modern warfare. These fuses usually embody an air driven vane for arming the firing mechanism. In one well-known fuse of this type, the vane is adapted torotate three sectors forming an annular safety member that is adapted to restrict movement of a striker and firing pin. Normally, the sectors are held in safety or unarmed position by a sleeve which extends into grooves cut in the sectors. Rotation of the vane i effective to withdraw this sleeve whereupon the sectors are released and are thrown radially by centrifugal force to arm the firing mechanism.

The sectors heretofore used were formed of aluminum to reduce the centrifugal forces and were so constructed as to require a large hole in the outer end of the arming sleeve so that the sectors could be telescoped over said sleeve and held thereon. When bombs fitted with this type of fuse wer dropped from a dive bomber, each safety sector was subjected to a very high centrifugal force and tended to move outwardly,

thereby exerting a, Strong pressure radially on the arming sleeve and causing drag on the arming sleeve. Frequently the gearing actuated by the vane for retracting the sleeve was stripped, due to this drag, thereby rendering the fuse inoperable. Any attempt to form the sectors of cheaper material, such as low grade steel, increased the centrifugal forces and rendered the device inoperative at diving speeds in excess of 100 miles per hour.

One of the objects of the present invention is to provide a novel fuse which will overcome the above difficulties.

Another object is to provide novel means for positively retaining the firing mechanism of a nose fuse in unarmed position until the bomb is released.

Further objects are to provide a bomb fuse of parts throughout the several views. It is to be expressly understood, however, that the drawing i for the purpose of illustration only, and is not designed as a definition of the limits of the invention, reference for this latter purpose being had primarily to the appended claims. In the drawi Fig. 1 is a longitudinal section through a bomb nose fuse embodying the present invention;

Fig. 2 is a longitudinal section showing the parts in armed position, and

Fig. 3 is a perspective of the safety block which is preferably employed.

In the form illustrated, the fuse comprises a body member 4 adapted to be threaded into the nose of a, bomb, not shown. Preferably this body portion is made of steel rather than aluminum, as has heretofore been the general practice, and is recessed at the inner end thereof to receive the usual booster charge. A recess 4a is centrally disposed in the outer portion of body 4 to receive the usual primer, not shown. Threaded to body portion 4 is an outer body portion 5 provided with an interior shoulder 6 to receive an end plate I, that separates the gear chamber Ba from the primer recess. The outer end of body portion 5 is formed as an inner ball race for balls 8, the outer race 9 serving as the hub for a two bladed vane I0. The vane has a circular hub portion Illa which is clamped between outer race 9 and a nut I I threaded onto the outer end of arming hub I2. Preferably, member 5, outer race 9 and nut II are formed of steel, while the arming hub I2 is of brass or bronze. Outer race 9 is threaded to arming hub I2 and the inner end of the arming hub extends into the gear chamber 6a and carries, at the extremity thereof, a ring gear I3. Outward movement of arming hub I2 relative to body portion 5 is prevented by means of a shoulder I2a formed on said hub for engagement with an inner shoulder 5a formed on body member 5. The vane I0, outer race 9, nut II, hub I2 and gear I3 thus rotate as a unit.

Gear I3 meshes with an elongated pinion I4 positioned in the gear chamber 6a and rotatably held in operative position by means of a pin I5 which extends through the pinion, the outer end of said pin extending into a recess formed in body member 5. Pinion I4 also meshes with a movable ring gear IE secured to the inner end of an arming sleeve 11 which extend through the longitudinal circular opening in arming hub I2. Gear I6 has more or less teeth than gear I3 so that rotation of pinion It will produce angular movement of said gears relative to each other in a direction to to the outer end thereof a striker ill in the form of a disc. The inner end of the firing pin is pointed and extend through a central opening in end plate '5. A coi1 spring 29 surrounds the firing pin with the outer end of said spring abutting against the inner face of the triker and the inner end of the coil sprin resting against the end plate I. A transversely extending pin 2! is carried by the firin pin 58 adjacent the inner end in a position to engage the inner face of end plate I whereby the firing pin and striker are held against movement outwardly relative to the fuse body.

Novel means are provided to prevent accidental arming of the firing mechanism of the fuse, said means being so formed and mounted that the fuse will be automatically armed when the bomb in which it is fitted is released from the aircraft.

As illustrated, there is provided a one-part, safety block 22 which loosely surrounds the projecting end of arming sleeve ll intermediate nut H and striker it. As is shown more clearly in Fig. 3, the safety block is an annular member 7 from which a parallel sided section has been cut, the width of the cut-out portion being greater than the maximum diameter of coil spring 29. An apertured guide 23 is preferably secured to the side of body portion 5 by means of screws (not shown), and vane It! may be. provided with diametricallydisposed tabs [0b, which tabs are also apertured similarly to guide 23. A sealing or arming wire 24 and an additional locking member (not shown), if desired, extends or extend through the apertures in the guide, and tab whereby movement of the vane is positively prevented. When arming wire 24 is removed and the bomb is released from the airplane bomb rack, vane l0 rotates at high speed together with hub I2 and gear l3. Pinion I4 is now rotated as is the gear l6 secured to the arming sleeve. Due to the operation of gear train it, Hi and it and the threaded connection between said sleeve and hub, the arming sleeve moves inwardly toward end plate 1 whereby the outer end of said sleeve is withdrawn fro-m the safety block 22.

The rush of air past the nose of the fuse causes the interrupted annular member or safety block 22 to move upwardly relative to striker l9 and to bear against the outer end of the rotating hub and this frictional engagement is sufficient to cause rotation of the block at high speed. When the outer end of the sleeve moves inwardly to the point where it is flush with the outer end of the hub, the centrifugal force acting on block 22 is effective to throw said block outwardly clear of the, spring and firin pin and the fuse is now armed. It will be apparent that the cut-out portion of the annular block unbalances the block so that centrifugal force is effective to insure that the block will be thrown outwardly clear of the spring and firing pin. In actual tests of the mechanism, it was found that the fuse would arm in one and two-tenths of a second at 450 miles per hour and in one second at 550 miles per hour. A successful test was also made at 600 miles per hour. The block may be made by cutting sections from a steel pipe which has a portion of the side wall thereof cut away. Even though the block is made 'ofsteel, arming of the fuse is certain because the centrifugal force is acting radially in one direction only rather than in three radial directions, as

in fuses heretofore provided. Moreover, the unbalance of the block is such that the centrifugal action never becomes excessive even when the block is made of steel. 5

There is thus provided a novel bomb nose fuse which is certain in operation, which is economi cal to construct, and which is operative at the high speeds required for modern bombing planes. Due to the substitution of inexpensive and available material, the bomb may be more readily fabricated. Various changes may be made in the details of the mechanism without departing from the invention.

What is claimed is: I

1.111 a bomb fuse of the type having a body from which projects an arming sleeve adapted to be retracted into said body by an air driven vane and a headed firing pin extending through said sleeve, the combination with said sleeve and pin of a one-piece annular safety block having a cut-out portion of width less than the sleeve but of sufficient size for escape when the sleeve is retracted, said block being adapted to surround said sleeve, in its unarmed position, be-

tween the head of the firing pin and'said body.

WILLIAM F. ERRIG. EDWARD s. DE HART. 

